Watches including a housing in which may be engaged and locked a support in which may be placed a battery for energizing the watch, are known and two examples thereof are to be discussed in this description. Here in fact it concerns enabling the watch wearer himself to change the battery of his watch without calling on a person skilled in the art. According to the design of the watch, the battery may be introduced either by the back cover and held in place by means of a screwed-in stopper, or at the side thereof and supported in such case by a drawer. Locking and unlocking of the support, stopper or drawer, may be effected by means of a tool delivered upon purchase of the watch, such tool being of such nature as may be readily misplaced or forgotten by the wearer when it is necessary to change the battery. In order to avoid such tool, solutions have already been proposed which, as may be seen hereinafter, call on the use of either a coin or of a bracelet buckle, such solutions not necessarily being the most felicitous for reasons which will appear hereinafter.